New sound system,quality, and pricing?

Hey guys, I'm looking into investing into a sound system for my bedroom. My bedroom is basically just a square, and I have the way I want this system set up visualized in my head already. I want one large speaker in each corner of the room (4 total), and it needs to be able to plug into my iPhone so I can play music directly from my phone. Now, the real question I am asking here is what are good quality, loud speakers I can get at a reasonable price, also with an audio jack that I can plug into my phone? thanks for reading and please respond below.